class SymbolTable:
    def __init__(self):
        self.symbols = {}
        self.parent = None
        
        
    
    def get(self, name):
        value = self.symbols.get(name, None)
        if value == None and self.parent:
            return self.parent.get(name)
        
        return value
    
    def set(self,name,value):
        self.symbols[name] = value
    
    def remove(self, var_name):
        del self.symbols[var_name]